In a certain code language, R + T means ‘R is the sister of T’. R – T means ‘R is the father of T’. R * T means ‘R is the wife of T’. R ÷ T means ‘R is the mother of T’. Based on the above, how is M related to Q if ‘M * N – P + Q ÷ R +T’?
- (a)Mother’s mother
- (b)Mother
- (c)Mother’s sister
- (d)Sister
Answer
Why
Correct — B.
Rule: take the links in the order written and stop the moment M and Q are joined.
M * N: M is the wife of N.
N – P: N is the father of P.
P + Q: P is the sister of Q, so P and Q are siblings.
Siblings share parents, so the father of P is also the father of Q. That makes N the father of Q.
M is N's wife, so M is Q's mother → option (b).
The last two links, Q ÷ R and R + T, describe Q's own child and are not needed for this relation.
Why the others are wrong
- (a)Mother’s mother — Mother's mother needs two generations between M and Q. There is only one here: M is married to N, and N is Q's own father, so M sits exactly one step above Q.
- (c)Mother’s sister — Mother's sister would make M a sibling of Q's mother. But the star in M * N makes M the wife of Q's father, which puts M in the parent role, not beside it.
- (d)Sister — Sister is Q's relation to P, not to M. P + Q is the sibling link; M enters the chain a generation higher through the marriage to N.
Concept
Symbol-coded relations are solved link by link, never by guessing from the letters. A, B, M and Q carry no gender; the relation words do.
Two of the four symbols here fix gender on their own. Wife of makes the left-hand letter female, and sister of does the same. That is how you know M is a mother rather than a father.
The other habit worth building is stopping early. A chain often runs past the two people the question asks about, and the extra links exist to be discarded.
Reading the chain from the wrong end reverses every parent link, which is the single most expensive error in this item type. Work strictly left to right.
Key facts
- R * T means R is the wife of T, so the letter before the star is female.
- R + T means R is the sister of T, which makes R female and makes R and T siblings.
- R – T means R is the father of T, and R ÷ T means R is the mother of T.
- A sibling link passes parents along: if N fathers P and P is Q's sister, then N fathers Q.
Study next
Common traps
- Reading the chain right to left, which inverts every parent link.
- Assuming Q is female because Q is described through a sister.
- Carrying the unused tail of the chain into the answer and jumping a generation.
This exact symbol set is used again at 09 Sep 2024, 12:30, Reasoning Q.9, which defines the same four symbols in the same words, then runs a longer chain and asks how F is related to C.
Read the definitions every time even when they look familiar. At 13 Sep 2024, 09:00, Reasoning Q.11 the plus means father and the minus means brother — neither of them what they mean here.
Related PYQs
No directly related past PYQ was found.